Electrically conductive timing belt

Abstract

An electrically conductive article (1) which maintains the conductive property over an extended use life is comprised of an electrically conductive thermoplastic layer (8) on the surface which is in contact with another article. When forming belts for synchronous drive systems, in addition to maintaining the electrical properties, the conductive layer exhibits high abrasion resistance and good tooth formation. A bonding layer (9) may be provided between the article body and the conductive layer (8).

What is claimed is:  
     
       1. A power transmission belt ( 1 ) including a material in the belt that tends to build an electrical charge during normal use when in contact with another article with which the belt has relative movement, the belt ( 1 ) comprising a body ( 2 ) and a cover layer ( 8 ) on an innermost surface ( 4 ) intended to be in contact with the another article, the belt ( 1 ) being characterized by 
       the innermost surface ( 4 ) having at least one row of adjacent rows of teeth ( 5 ), and the cover layer ( 8 ) being an electrically conductive polyethylene thermoplastic.  
     
     
       2. The belt ( 1 ) in accordance with  claim 1  wherein the cover layer ( 8 ) is ultra high molecular weight polyethylene. 
     
     
       3. The belt ( 1 ) in accordance with  claim 1  or  2  wherein the thickness of cover layer ( 8 ) is within the range of 0.05 to 0.25 mm (0.002 to 0.01 inches). 
     
     
       4. The belt ( 1 ) in accordance with  claim 1  or  2  wherein a bonding layer ( 9 ) is adjacent the cover layer ( 8 ). 
     
     
       5. The belt ( 1 ) in accordance with  claim 4  wherein the bonding layer ( 9 ) is high density polyethylene. 
     
     
       6. The belt ( 1 ) in accordance with  claim 1  wherein the belt ( 1 ) has an initial surface electrical resistance of not more than 0.05 M ohms. 
     
     
       7. The belt ( 1 ) in accordance with  claim 1  wherein the belt ( 1 ) comprises a fabric layer ( 7 ) adjacent the cover layer ( 8 ).